More than 1,300 nursing homes in the U.S., most of them for-profit facilities, experienced extremely high COVID-19 infection rates in 2020, according to a new report from the Office of the Inspector General (OIG) for the Department of Health and Human Services.

For the OIG’s study, the agency took Medicare claims data to find nursing homes with beneficiaries who tested positive for COVID-19. The study looked at 15,086 nursing homes across the country.

“Nursing homes had a surge of COVID-19 cases during the spring of 2020 and a greater surge during the fall, well after they were known to be vulnerable. More than 1,300 nursing homes had extremely high infection rates — 75 percent or more of their Medicare beneficiaries — during these surges,” the OIG said.

Nursing homes with extremely high infection rates also saw rises in their overall mortality.

The report noted demographic differences across the two surges that were observed. During the first surge in cases, urban nursing homes were more likely to have a high number of cases, while rural ones were likely to have a high rate of cases in the second surge.

In both surges that the OIG analyzed, for-profit nursing homes accounted for a “disproportionate” number of locations with extreme infection rates.

The OIG’s survey did not detect a lack of infection controls among the majority of nursing homes that reported extremely high infection rates, and transmission rates among counties did not always lead to high case rates in nursing homes within those counties.

In light of the report’s findings, the OIG recommended that the Centers for Medicare and Medicaid Services (CMS) examine nursing staff requirements and revise them if necessary, improve on how surveys find infection control risks and target nursing homes in need of infection control intervention.

According to the OIG, the CMS concurred with the first and third recommendations that were issued while neither agreeing or disagreeing with the second recommendation.